Bumblebees,
by, John B. Free and Colin G. Butler. With two appendices by Ian H.H. Yarrow. Illustrated with 46 photos. by Colin G. Butler.

APA Citation

Free, J. Brand., Butler, C. G. (Colin Gasking). (1959). Bumblebees. New York: Macmillan.

MLA Citation

Free, John Brand, and Colin G. (Colin Gasking) Butler. Bumblebees. New York: Macmillan, 1959.

Warning: These citations may not always be complete (especially for serials).